Toughened prepregs and formulations

Abstract

A prepreg formulation comprising prepreg fabric or filament fibers unidirectionally aligned and a toughened resin system comprising a thermosetting matrix resin and a small amount of a chromium (III) complex. In another embodiment, the invention includes the presence of thin surface layers of extremely fine fibers of a thermoformable polymer having at least one of a T m or T g greater than about 300° C. or no T m or T g and a decomposition temperature greater than about 300° C. In another embodiment, the invention includes the presence of inorganic fine fibers. The preferred matrix resin is a blend of a thermosetting epoxy resin and an amorphous thermoplastic polymer having a T g greater than about 195° C.

We claim: 
     
       1. A prepreg formulation comprising prepreg fabric and/or filament fibers unidirectionally aligned, a thermosetting matrix resin of a mixed resin and a small amount of a chromium (III) complex. 
     
     
       2. The prepreg formulation of claim 1 wherein there is present thin surface layers of extremely fine fibers, fibrids or particles of a thermoformable polymer having at least one of a T m  or T g  greater than about 300° C. or no T m  or T g  and a decomposition temperature greater than about 300° C. 
     
     
       3. The prepreg formulation of claim 1 wherein the matrix resin is a blend of a thermosetting epoxy resin and an amorphous thermoplastic polymer having a T g  greater than about 195° C. 
     
     
       4. The prepreg formulation of claim 3 wherein the amorphous thermoplastic polymer is one or more of a polyethersulfone, a polyarlsulfone and a polyetherimide. 
     
     
       5. The prepreg formulation of claim 2 wherein the extremely fine fiber is present in an amount of about 0.25 to about 5 weight % based on the weight of the matrix resin. 
     
     
       6. The prepreg formulation of claim 3 wherein the epoxy resin comprises a low viscosity glycidyl epoxy resin. 
     
     
       7. The prepreg formulation of claim 1 wherein there is present a a small concentration of inorganic whiskers. 
     
     
       8. The prepreg formulation of claim 7 wherein the whiskers are ceramic. 
     
     
       9. The prepreg formulation of claim 6 wherein there is present small amount of a thermoplastic having a T g  less than about 195° C. 
     
     
       10. A laminate formed of the prepreg formulations of claim 1. 
     
     
       11. A laminate formed of the prepreg formulations of claim 2. 
     
     
       12. A laminate formed of the prepreg formulations of claim 3. 
     
     
       13. A laminate formed of the prepreg formulations of claim 4. 
     
     
       14. A laminate formed of the prepreg formulations of claim 5. 
     
     
       15. A laminate formed of the prepreg formulations of claim 6. 
     
     
       16. A laminate formed of the prepreg formulations of claim 7. 
     
     
       17. A laminate formed of the prepreg formulations of claim 8. 
     
     
       18. A laminate formed of the prepreg formulations of claim 9. 
     
     
       19. A matrix resin composition comprising a thermosetting matrix resin of a mixed resin and a small amount of a chromium (III) complex. 
     
     
       20. The matrix resin of claim 19 wherein the resin comprises a small quantity of extremely fine fibers, fibrids or particles of a thermoformable polymer having at least one of a T m  or T g  greater than about 300° C. or no T m  or T g  and a decomposition temperature greater than about 300° C. 
     
     
       21. The matrix resin composition of claim 19 wherein the resin is a blend of a thermosetting epoxy resin and an amorphous thermoplastic polymer having a T g  greater than about 195° C. 
     
     
       22. The matrix resin composition of claim 20 wherein the amorphous thermoplastic polymer is one or more of a polyethersulfone, a polyarylsulfone and a polyetherimide. 
     
     
       23. The matrix resin composition of claim 20 wherein the extremely fine fiber is present in an amount of about 0.25 to about 5 weight % based on the weight of the matrix resin. 
     
     
       24. The matrix resin composition of claim 21 wherein the epoxy resin comprises a low viscosity glycidyl epoxy resin. 
     
     
       25. The matrix resin composition of claim 19 wherein there is present a small concentration associated with the aforementioned fine fibers, fibrids or particles, of inorganic whiskers. 
     
     
       26. The matrix resin composition of claim 25 wherein the whiskers are ceramic. 
     
     
       27. The matrix resin composition of claim 24 wherein there is present small amount of a thermoplastic having a T g  less than about 195° C.